I found this wind direction measurement circuit simple and interesting. If you are doing some home automation project, this might be another sensor included in your project.
For Wind direction measurement, you will need a circle from some material (you might even use a CD.) Then stick an arrow on top. One end of the arrow should have a fin. Another end of the arrow should have a piece of magnet. Then put eight magnetic sensors around the circle in the magnet’s way. See drawing:
I think the working of this sensor is very obvious. Turning Arrow depending on wind direction, turns ON magnetic switches.
The circuit has 8 outputs corresponding to the wind direction. These outputs can be connected to a simple indication circuit, which can be in your room:
Depending on the switch turned on, the led indicator shows where the wind blows.
Of course, this sensor can be easily adapted to any embedded system and display results on LCD or log changes in EEPROM memory for further analysis.